This invention is generally directed to toner compositions, and more specifically, the present invention relates to developer compositions having incorporated therein toner compositions comprised of semicrystalline polyolefin resins. More specifically, in one embodiment of the present invention there are provided developer compositions formulated by admixing toner compositions containing polyolefin toner polymeric resins, and carrier components. In one specific embodiment of the present invention there are provided toner compositions with a semicrystalline polyolefin resin, alpha-olefin polymers, copolymers, or mixtures, thereof, which components are nontoxic, nonblocking at temperatures of less than 50.degree. C., for example, jettable or processable into toner compositions by other means, melt fusable with a broad fusing temperature latitude, cohesive above the melting point of the resin, and triboelectrically chargable. Moreover, in addition the toner compositions of the present invention possess lower fusing temperatures, and therefore lower fusing energies are required for fixing thus enabling less power consumption during fusing, and permitting extended lifetimes for the fuser systems selected. Accordingly, thus the toners of the present invention can be fused (fuser roll set temperature) at temperatures of 225.degree. F. or less as compared to many currently commercially available toners which fuse at temperatures of from about 300.degree. to about 325.degree. F. With further respect to the present invention, the semicrystalline alpha-olefin polymers or copolymers selected have a melting point of from about 50.degree. to about 100.degree. C., and preferably from about 60.degree. to about 80.degree. C. as determined by DSC and by other known methods. Also, the toner, and developer compositions of the present invention are particularly useful in electrophotographic imaging and printing systems, especially xerographic imaging processes.
The electrostatographic process, and particularly the xerographic process, is well known. This process involves the formation of an electrostatic latent image on a photoreceptor, followed by development, and subsequent transfer of the image to a suitable substrate. Numerous different types of xerographic imaging processes are known wherein, for example, insulative developer particles or conductive toner compositions are selected depending on the development systems used. Moreover, of importance with respect to the aforementioned developer compositions is the appropriate triboelectric charging values associated therewith, as it is these values the enable continued constant developed images of high quality and excellent resolution; and admixing characteristics. Specifically, thus toner and developer compositions are known, wherein there are selected as the toner resin styrene acrylates, styrene methacrylates, and certain styrene butadienes including those available as Pliolites. Other resins have also have been selected for incorporation into toner compositions inclusive of the polyesters as illustrated in U.S. Pat. No. 3,590,000. Moreover, it is known that single component magnetic toners can be formulated with styrene butadiene resins, particularly those resins available as Pliolite. In addition, positively charged toner compositions containing various resins, inclusive of certain styrene butadienes and charge enhancing additives, are known. For example, there are described in U.S. Pat. No. 4,560,635, the disclosure of which is totally incorporated herein by reference, positively charged toner compositions with distearyldimethyl ammonium methylsulfate charge enhancing additives. This patent also illustrates the utilization of suspension polymerized styrene butadienes for incorporation into toner compositions, reference for example working Example IX.
Numerous patents are in existance that illustrate toner compositions with various types of toner resins including, for example, 4,104,066, polycaprolactones; 3,547,822, polyesters; 4,049,447, polyesters; 4,007,293, polyvinyl pyridine-polyurethane; 3,967,962, polyhexamethylene sebaccate; 4,314,931, polymethyl methacrylates; Reissue 25,136, polystyrenes; and 4,469,770, styrene butadienes.
Of particular interest in U.S. Pat. No. 4,529,680, which discloses magnetic toners for pressure fixation containing methyl-1-pentene as the main component. More specifically, there is illustrated in this patent, reference column 2, beginning at line 66, magnetic toners with polymers containing essentially methyl-1-pentene as the main component, which polymer may be a homopolymer or copolymer with other alpha-olefin components. It is also indicated in column 3, beginning at around line 14, that the intrinsic viscosity of the polymer is of a specific range, and further that the melting point of the polymer is in a range of 150.degree. to 240.degree. C., and preferably 180.degree. to 230.degree. C. Other patents of background interest located as a result of a patentability search include 3,720,617; 3,752,666; 3,788,994; 3,983,045; 4,051,077; 4,108,653; 4,258,116; and 4,558,108.
In addition, several recently issued patents illustrate toner resins including vinyl polymers, diolefins, and the like, reference for example U.S. Pat. No. 4,560,635. Moreover, there is illustrated in U.S. Pat. No. 4,469,770 toner and developer compositions wherein there is incorporated into the toner styrene butadiene resins prepared by emulsion polymerization processes.
Furthermore, a number of different carrier particles have been illustrated in the prior art, reference for example the 3,590,000 patent mentioned herein; and U.S. Pat. No. 4,233,387, the disclosure of which is totally incorporated herein by reference, wherein coated carrier components for developer mixtures, which are comprised of finely divided toner particles clinging to the surface of the carrier particles, are recited. Specifically, there is disclosed in this patent coated carrier particles obtained by mixing carrier core particles of an average diameter of from between about 30 microns to about 1,000 microns with from about 0.05 percent to about 3.0 percent by weight based on the weight of the coated carrier particles of thermoplastic resin particles. More specifically, there are illustrated in the '387 patent processes for the preparation of carrier particles by a powder coating process; and wherein the carrier particles consist of a core with a coating thereover comprised of polymers. The carrier particles selected can be prepared by mixing low density porous magnetic, or magnetically attractable metal core carrier particles with from, for example, between about 0.05 percent and about 3 percent by weight based on the weight of the coated carrier particles of a polymer until adherence thereof to the carrier core by mechanical impaction or electrostatic attraction; heating the mixture of carrier core particles and polymer to a temperature, for example, of between from about 200.degree. F. to about 550.degree. F. for a period of from about 10 minutes to about 60 minutes enabling the polymer to melt and fuse to the carrier core particles; cooling the coated carrier particles; and thereafter classifying the obtained carrier particles to a desired particle size. In copending applications U.S. Ser. Nos. 136,792 and 136,791, the disclosures of which are totally incorporated herein by reference, there are disclosed carrier particles comprised of a core with a coating thereover comprised of a mixture of a first dry polymer component and a second dry polymer component not in close proximity to the first polymer in the triboelectric series. Therefore, the aforementioned carrier compositions can be comprised of known core materials including iron with a dry polymer coating mixture thereover. Subsequently, developer compositions can be generated by admixing the aforementioned carrier particles with a toner composition comprised of resin particles and pigment particles.
In copending application U.S. Ser. No. 751,922 entitled Developer Compositions With Specific Carrier Particle Developers, the disclosure of which is totally incorporated herein by reference, there are illustrated toners with styrene butadiene copolymers, pigment particles inclusive of magnetites, charge control additives, and carrier particles containing a core with a coating thereover of vinyl copolymers, or homopolymers such as vinyl chloride/vinyl acetate.
Other patents of interest include 3,939,086, which teaches steel carrier beads with polyethylene coatings, see column 6; 3,533,835; 3,658,500; 3,798,167; 3,918,968; 3,922,382; 4,238,558; 4,310,611; 4,397,935; and 4,434,220.
Although the above described toner compositions and resins are suitable for their intended purposes, in most instances there continues to be a need for toner and developer compositions containing new resins. More specifically, there is a need for toners, which can be fused at lower energies than many of the presently available resins selected for toners. There is also a need for resins that can be selected for toner compositions which are low cost, nontoxic, nonblocking at temperatures of less than 50.degree. C., jettable, melt fusible with a broad fusing latitude, cohesive above the melting temperature, and triboelectrically chargable. In addition, there remains a need for toner compositions which can be fused at low temperatures, that is for example 25.degree. F. (275.degree. F., for example) or less, as compared to those presently in commercial use, which require fusing temperature of about 300.degree. to 325.degree. F., thereby enabling with the compositions of the present invention the utilization of lower fusing temperatures, and lower fusing energies permitting less power consumption during fusing, and allowing the fuser system, particularly the fuser roll selected, to possess extended lifetimes. Another need resides in the provision of developer compositions comprised of the toner compositions illustrated herein, and carrier particles. There also remains a need for toner and developer compositions containing additives therein, for example charge enhancing components, thereby providing positively, or negatively charged toner compositions. Furthermore, there is a need for toner and developer compositions with semicrystalline polyolefin polmers that will enable the generation of solid image area with substantially no background deposits, and full gray scale production of half tone images in electrophotographic imaging and printing systems.
There is also a need for semicrystalline alpha-olefin polymers, copolymers thereof, and mixtures of the aforementioned polymers and copolymers with melting points of from about 50.degree. to about 100.degree. C., and preferably from about 60.degree. to about 80.degree. C.; and wherein toner compositions containing the aforementioned resins can be formulated into developer compositions which are useful in electrophotographic imaging and printing systems, and wherein fusing can, for example, be accomplished by flash, radiant, with heated ovens, and cold pressure fixing methods.